He said �Not pictured is the 18 inch piece of culvert pipe I put over this that acts as a pit. I ran a 4 inch piece of pipe to the surface with a grate flush with the ground for the air to enter. I also capped the pit with a concrete cap and covered it with dirt and grass.� I�m assuming he capped the pit containing the the siphon pipes and vent pipe and ran a 4� pipe from the pit to ground level. Do you think this could be done with a single siphon pipe and vent pipe being completely buried without having a pit and relying on the amount of air contained in the vent pipe above the apex of the siphon pipe? Wouldn�t there always be available air in the vent pipe without having a pit? If you positioned the 2� vent pipe higher than the siphon pipe drilling holes in the 2� vent pipe from the apex level of the siphon pipe and extended it approximately two feet through a 4� adapter that then attaches to a 4� piece of pipe. The 4� pipe would be in the pond covered with rock and the water level would rise through that piece of 4� pipe until it reached the 2� vent pipe with holes drilled into it until the water met the highest hole at the apex of the siphon pipe. Would this not then create a siphon that was broken only when the water level receded below the holes at the apex level of the siphon pipe in the vent pipe? The 4� pipe would be higher than the apex of the siphon pipe. This maybe a little bit confusing but all of the 2� vent pipe with holes would be encased inside the 4� pipe using the adapter. You would still have solid 2� vent pipe coming from your tee in the siphon pipe until it reached the adapter. Isn�t there always air in the siphon pipe when it is not in siphon mode?
Heppy